September 27, 2010

Puberty Strikes Sooner When the Father Isn’t Present

(Ivanhoe Newswire) "“ Look out moms! Girls who live in a home without a father are more likely to hit puberty at an earlier age.

The study found that in a home where the biological father was absent, the daughter developed breasts and pubic hair quicker. This is only true for girls in high-income homes.

"The age at which girls are reaching puberty has been trending downward in recent decades, but much of the attention has focused on increased body weight as the primary culprit," the study's lead author, Julianna Deardorff, UC Berkeley assistant professor of maternal and child health was quoted as saying. "While overweight and obesity alter the timing of girls' puberty, those factors don't explain all of the variance in pubertal timing. The results from our study suggest that familial and contextual factors "“ independent of body mass index "“ have an important effect on girls' pubertal timing."

The findings came from the Cohort study of Young Girls' Nutrition, Environment and Transitions (CYGNET). "Although the main focus of the CYGNET Study is on environmental exposures, we are also keenly interested in the social and behavioral contexts in which maturation occurs," Lawrence Kushi, associate director of etiology and prevention research at the Kaiser Permanente Northern California Division of Research was quoted as saying. "These findings demonstrate that such factors may play important roles in the onset of puberty in girls."

There has already been a link between lack of a father figure and early onset of puberty, but those studies didn't take into account body mass index, ethnicity, and income. In this new study researchers recruited 444 girls between the ages of 6-8, and have been following them up annually. Their analysis was for two years. They considered signs of puberty that occur before the start of menarche. In interviews with the girls' caregivers, the researchers asked about the residents in the girls' homes and their relationships to the children.

Of the girls studied 80 reported the lack of a biological father at the time of recruitment. The girls who lived in a high income family had earlier breast development. Earlier onset of pubic hair only occurred in high income African American girls.

Some scientists believe that the lack of a father triggers an unstable family environment bringing puberty on sooner. "It's possible that in lower income families, it is more normative to rely upon a strong network of alternative caregivers," said Deardorff. "A more controversial hypothesis is that higher income families without fathers are more likely to have a single mother who works long hours and is not as available for care giving. Recent studies have suggested that weak maternal bonding is a risk factor for early puberty."

"The hunt for an explanation to this trend is significant since girls who enter puberty earlier than their peers are not only at greater risk for reproductive cancers, they are also more likely to develop asthma and engage in higher risk sexual behaviors and substance abuse, so these studies have broader relevance to women's health," Bay Area BCERC's principal investigator Dr. Robert Hiatt, UCSF professor and co-chair of epidemiology and biostatistics, and director of population science at the campus's Helen Diller Family Comprehensive Cancer Center was quoted as saying.